Diabetic autonomic neuropathy alters heart rate control (tachy) and vascular function (dilation of vasculature). Also, it has been reported that the incidence and severity of angina, acute myocardial infarction, and congestive heart failure is greater for diabetics than non-diabetic patients.
A healthy heart produces a constant and plentiful supply of adenosine triphosphate (ATP), an energy molecule required for cells to function. ATP is primarily produced by the metabolism of carbohydrates, fatty acids and proteins. The primary metabolized carbohydrate is glucose, which is a more efficient energy source for the heart than fatty acids as fatty acids require approximately 10% more oxygen to produce an equivalent amount of ATP.
Diabetes can change cardiac energy metabolism, which can contribute to reduced cardiac contractility and ischemic injury. For a healthy heart, fatty acid oxidation typically provides 60 to 70% of the ATP but can provide 90 to 100% of the ATP for patients with uncontrolled diabetes. Thus, diabetic hearts work harder, demand more oxygen and make the heart prone to ischemia and arrhythmias. Myocardial metabolic alterations can cause increased asymptomatic ischemia, acute myocardial infarction, reduced survival post myocardial infarction, and changes in the excitation-contraction coupling of the myocardium thereby leading to diabetic cardiomyopathy.